/*
This file is part of Caelum.
See http://www.ogre3d.org/wiki/index.php/Caelum 

Copyright (c) 2006-2007 Caelum team. See Contributors.txt for details.

Caelum is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Caelum is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with Caelum. If not, see <http://www.gnu.org/licenses/>.
*/
#include "CaelumPrecompiled.h"
#include "SkyDome.h"
#include "CaelumExceptions.h"
#include "InternalUtilities.h"

using namespace Caelum;

const Ogre::String SkyDome::SPHERIC_DOME_NAME = "CaelumSphericDome";
const Ogre::String SkyDome::SKY_DOME_MATERIAL_NAME = "CaelumSkyDomeMaterial";


//-----------------------------------------------------------------------------
/// Constructor
SkyDome::SkyDome(Ogre::SceneManager *sceneMgr, Ogre::SceneNode *caelumRootNode)
{
   String uniqueSuffix = "/" + InternalUtilities::pointerToString(this);

   // First clone material
   mMaterial.reset(InternalUtilities::checkLoadMaterialClone(SKY_DOME_MATERIAL_NAME, SKY_DOME_MATERIAL_NAME + uniqueSuffix));

   // Determine if the shader technique works.
   mShadersEnabled = mMaterial->getBestTechnique()->getPass(0)->isProgrammable();

   // Force setting haze, ensure mHazeEnabled != value.
   mHazeEnabled = true;
   setHazeEnabled(false);

   sceneMgr->getRenderQueue()->getQueueGroup(CAELUM_RENDER_QUEUE_SKYDOME)->setShadowsEnabled(false);

   // Generate dome entity.
   InternalUtilities::generateSphericDome (SPHERIC_DOME_NAME, 32, InternalUtilities::DT_SKY_DOME);
   mEntity.reset(sceneMgr->createEntity ("Caelum/SkyDome/Entity" + uniqueSuffix, SPHERIC_DOME_NAME));
   mEntity->setMaterialName (mMaterial->getName());
   mEntity->setRenderQueueGroup (CAELUM_RENDER_QUEUE_SKYDOME);
   mEntity->setCastShadows (false);

   mNode.reset(caelumRootNode->createChildSceneNode ("Caelum/SkyDome/Node" + uniqueSuffix));
   mNode->attachObject (mEntity.get());
}

SkyDome::~SkyDome () {
}

void SkyDome::notifyCameraChanged (Ogre::Camera *cam) {
   CameraBoundElement::notifyCameraChanged (cam);
}

void SkyDome::setFarRadius (Ogre::Real radius) {
   CameraBoundElement::setFarRadius(radius);
   mNode->setScale (Ogre::Vector3::UNIT_SCALE * radius);
}


/// Sets the sun direction.
void SkyDome::setSunDirection (const Ogre::Vector3& sunDir)
{
   Ogre::Real elevation = sunDir.dotProduct (Ogre::Vector3::UNIT_Y);
   elevation = elevation * 0.5f + 0.5f;

   if (mShadersEnabled)
   {
      mParams.sunDirection.set(mParams.vpParams, sunDir);
      mParams.offset.set(mParams.fpParams, elevation);
   }
   else
   {
      Ogre::Pass* pass = mMaterial->getBestTechnique()->getPass(0);
      Ogre::TextureUnitState* gradientsTus = pass->getTextureUnitState(0);
      gradientsTus->setTextureUScroll (elevation);
   }
}

void SkyDome::setHazeColour (const Ogre::ColourValue& hazeColour) {
   if (mShadersEnabled && mHazeEnabled) {
      mParams.hazeColour.set(mParams.fpParams, hazeColour);
   }    
}

void SkyDome::setSkyGradientsImage (const Ogre::String& gradients)
{
   Ogre::TextureUnitState* gradientsTus =
      mMaterial->getTechnique (0)->getPass (0)->getTextureUnitState(0);

   gradientsTus->setTextureAddressingMode (Ogre::TextureUnitState::TAM_CLAMP);

   // Per 1.4 compatibility. Not tested with recent svn.
#if OGRE_VERSION < ((1 << 16) | (3 << 8))
   gradientsTus->setTextureName (gradients, Ogre::TEX_TYPE_2D, -1, true);
#else
   gradientsTus->setTextureName (gradients, Ogre::TEX_TYPE_2D);
   gradientsTus->setIsAlpha (true);
#endif
}

void SkyDome::setAtmosphereDepthImage (const Ogre::String& atmosphereDepth)
{
   if (!mShadersEnabled) {
      return;
   }

   Ogre::TextureUnitState* atmosphereTus =
      mMaterial->getTechnique (0)->getPass (0)->getTextureUnitState(1);

   atmosphereTus->setTextureName (atmosphereDepth, Ogre::TEX_TYPE_1D);
   atmosphereTus->setTextureAddressingMode (Ogre::TextureUnitState::TAM_CLAMP, Ogre::TextureUnitState::TAM_WRAP, Ogre::TextureUnitState::TAM_WRAP);
}

bool SkyDome::getHazeEnabled () const {
   return mHazeEnabled;
}

void SkyDome::setHazeEnabled (bool value)
{
   if (mHazeEnabled == value) {
      return;
   }
   mHazeEnabled = value;

   if (!mShadersEnabled) {
      return;
   }

   Ogre::Pass *pass = mMaterial->getTechnique (0)->getPass (0);
   if (value) {
      pass->setFragmentProgram("CaelumSkyDomeFP");
   } else {
      pass->setFragmentProgram("CaelumSkyDomeFP_NoHaze");
   }
   mParams.setup(
      pass->getVertexProgramParameters(),
      pass->getFragmentProgramParameters());
}

void SkyDome::Params::setup(Ogre::GpuProgramParametersSharedPtr vpParams, Ogre::GpuProgramParametersSharedPtr fpParams)
{
   this->fpParams = fpParams;
   this->vpParams = vpParams;
   sunDirection.bind(vpParams, "sunDirection");
   offset.bind(fpParams, "offset");
   hazeColour.bind(fpParams, "hazeColour");
}
